1. Field of the Invention
The invention relates generally to can ends and, more particularly, to a can end scoring method. The invention also relates to tooling assemblies for scoring can ends. The invention further relates to conversion presses for providing scored can ends.
2. Background Information
Metallic containers (e.g., cans) for holding products such as, for example, food and beverages, are typically provided with an easy open can end on which a pull tab is attached (e.g., without limitation, riveted) to a tear strip or severable panel. The severable panel is defined by a scoreline in the exterior surface (e.g., public side) of the can end. The pull tab is structured to be lifted and/or pulled to sever the scoreline and deflect and/or remove the severable panel, thereby creating an opening for dispensing the contents of the can.
When the can end is made, it originates as a can end shell, which is formed from a sheet metal product (e.g., without limitation, sheet aluminum; sheet steel). The shell is then conveyed to a conversion press, which has a number of successive tool stations. As the shell advances from one tool station to the next, conversion operations such as, for example and without limitation, rivet forming, paneling, scoring, embossing, tab securing and tab staking, are performed until the shell is fully converted into the desired can end and is discharged from the press. Typically, each tool station of the conversion press includes an upper tool member, which is structured to be advanced towards a lower tool member upon actuation of a press ram. The shell is received between the upper and lower tool members. Thus, as the upper tool member engages the shell, the upper and/or lower tool members respectively act upon the public and/or product (e.g., interior side, which faces the can body) sides of the shell, in order to perform a number of the aforementioned conversion operations. Upon completion of a given operation, the press ram retracts the upper tool member and the partially converted shell is moved to the next successive tool station, or the tooling is changed within the same station, to perform the next conversion operation.
FIG. 1, for example, shows a portion of a can end 1 (e.g., partially converted shell) disposed between the upper and lower tool members 3,5 of a conventional conversion press tool station 7. The upper tool member 3 includes a score knife 9, which is disposed opposite and spaced apart from a score anvil 11 of the lower tool member 5. The score anvil 11 supports the product side 15 of the can end 1 as the score knife 9 is brought into contact with the public side 13 and creates the scoreline 17 therein, as shown. It will be appreciated that the public and product sides 13,15 of the can end 1 typically include a protective coating (not shown). Scoring the public side 13 of the can end 1 to create the scoreline 17 removes this protective coating at the location of the scoreline 17, thereby exposing the underlying metal of the can end 1.
As shown in FIG. 2, after the scoring operation, a post score repair procedure is typically performed in an attempt to cover (e.g., spray; coat; seal) the scoreline 17 with a suitable sealant 19 (e.g., without limitation, repair agent) to resist oxidation of the exposed metal. However, it is difficult to effectively and efficiently cover the edges 21,23 of the scoreline 17. Specifically, the edges 21,23 form relatively sharp intersections between the exposed metal of the scoreline 17 and adjacent portions of the public side 13 of the can end 1. It is difficult to ensure that the sealant 19, which is shown in simplified form in FIG. 2, sufficiently coats and adheres to the can end 1 at these locations (e.g., edges 21,23). Moreover, in an attempt to address this concern, an excessive quantity of the sealant 19′ is sometimes applied to the can end 1, as shown in exaggerated form in phantom line drawing in FIG. 2.
There is, therefore, room for improvement in can end scoring methods, and in tooling assemblies and conversion presses for providing scored can ends.